Group: program control

topics > computer science > Group: programming

conditional control
repetitive control

control returning functions and expressions
dynamic code modification
flow diagrams and flow charts
goto statement
program blocks for control
return from procedure
structured flow diagram
structured programming
termination of control unit
exception handling

control file
control point
state machine
task scheduling


There are many alternatives for program control other than branching and block control. Control can be handshaking which maintains synchronization and signals completion of actions. It can be synchronous, asynchronous, sequential, parallel, monitoring, or absolute. It can be defined separately from computation with equations indicated by name, or defined as text reorganization, or driven by a data structure or physically defined surface. A system module may be defined solely for control, e.g., Comit rule schedulers. Control can be divided into its component parts such as creation of a context, invocation of a context, and resumption of a context. Control should be described statically even though it implies execution. Changes in context or environment may also be implied. Fortunately only a small number of control structures are actually used regularly. The most common is sequential structures with their implicit "execute next statement". (cbb 5/80)
Subtopic: sequential composition up

Quote: sequential composition is key to efficient programs because all computational resources immediately available at each step [»hoarCA9_1987]

Subtopic: control structures as implementation up

Quote: most texts explain control structures by tracing execution of some implementation, even though this is frowned upon in general [»hehnEC_1977]

Subtopic: generalized control up

Quote: it..ti combines loop and conditional constructs by repeatedly executing true guards until a downArrow is found [»parnDL8_1983]
Quote: most control computations follow a few general patterns [»pratT3_1978]

Subtopic: algebra of control structures up

Quote: develops an algebra of control structures; e.g., sequence, indexing, conditional, loop, loop exit [»voorEA6_1958, OK]
Quote: Kosaraju defined a hierarchy of control structures under semantic conversions; D and D' at bottom, L (goto) at top [»ledgHF11_1975, OK]
Quote: defines D and D' control structures: basic actions, composition, conditionals, repetitions [»ledgHF11_1975, OK]

Subtopic: semantic vs. path-wise equivalence up

Quote: program structures are semantically convertible if both compute the same function from the same set of primitive actions and predicates [»ledgHF11_1975, OK]
Quote: program structures are path-wise convertible if they define the same sequence of primitive actions and predicates for every input [»ledgHF11_1975, OK]

Subtopic: data structure traversal up

Quote: with ordered types and generalized for statements, data structure traversal is a high level control structure for the programming language [»abraH12_1977]
Quote: like pattern matching in a string, traverse data structures with directives [»hallJC5_1974]

Subtopic: programmed control up

Quote: Smalltalk defines a control structure as a class that creates and executes the necessary objects [»shocJF9_1979, OK]
Quote: to help construct control relationships, every environment can get its creator and its resumer [»hansDR5_1978]

Subtopic: feedback control up

Quote: APT has explicit and continuous motion positioning; the later compares tangents of the part surface, drive surface, and check surface [»browSA11_1963, OK]
Quote: in APT, the drive surface of a statement is the check surface of the previous statement [»browSA11_1963, OK]

Subtopic: dispatcher up

QuoteRef: sammJE_1969 ;;425 rules with labeled subrules (indented with blanks) with control determined by dispatcher

Subtopic: control flow up

QuoteRef: dennJB_1974 ;;364 links are typed as control arcs (true or false) and date arcs (integer real or string)
QuoteRef: kosiPR9_1973 ;;91 PRESENCE signals receiver that a datum exists on a path and DONE signal sender that data has been received

Subtopic: no control -- functional up

Quote: a functional program for matrix multiply contains no variables, no loops, no control statements, no initializations, no declarations

Subtopic: loop vs. non-loop branches up

Quote: in many programs, more non-loop branches occur than loop branches

Group: program control up

Group: conditional control   (7 topics, 142 quotes)
Group: repetitive control   (7 topics, 117 quotes)

Topic: co-routines (13 items)
Topic: continuation (16 items)
Topic: control returning functions and expressions (6 items)
Topic: dynamic code modification (15 items)
Topic: flow diagrams and flow charts (21 items)
Topic: goto statement (25 items)
Topic: program blocks for control (20 items)
Topic: recursion (16 items)
Topic: return from procedure (9 items)
Topic: save-restore (4 items)
Topic: structured flow diagram (36 items)
Topic: structured programming (27 items)
Topic: termination of control unit
(22 items)

Related Topics up

Group: exception handling   (12 topics, 314 quotes)

Topic: control file (10 items)
Topic: control point (3 items)
Topic: state machine (67 items)
Topic: task scheduling
(49 items)

Updated barberCB 11/04
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Thesa is a trademark of C. Bradford Barber.